I'm not certain on this, but I don't believe it can. I work with a dCas9 protein and it doesn't seem to bind to anything in my sgRNA-free controls. It would be pretty a pretty lousy immune system in bacteria if it did, too. Perhaps you could create a Cas9 enzyme with a sgRNA fused to it somehow? But that's beyond my depth.

That's another challenge in using a straight up Cas9 protein to cut DNA too, I think, since I'm not sure you'll be able to imitate the secondary structure of the sgRNA either.

Does any know if there is a company or a group that is selling or able to provide the CRISPR-CAS9 protein?

I would like to use the CRISPR system invitro to cut DNA. I can't use restriction enzymes.

Thanks

That is a very interesting idea. I am not sure whether earlier papers studying CRISPR have tried this like RNAi people have for in vitro RNAi. In this in vitro system, you need to add guide RNA which could be chemically synthesized.